Fill level and topology determination

ABSTRACT

An antenna apparatus for a fill level measurement device is provided, including an antenna configured to emit a measurement signal towards a filling material surface and to receive a reflected measurement signal reflected by the filling material surface; a motor configured to rotate the antenna about an axis of rotation; and an elongate focussing arrangement configured to focus the emitted measurement signal and/or the reflected measurement signal, wherein the antenna includes an array of a plurality of radiator elements configured to emit the measurement signal and/or to receive the reflected measurement signal.

FIELD OF THE INVENTION

The invention relates to the determination of the fill level andtopology of a filling material surface. The invention relates inparticular to an antenna apparatus for a fill level measurement device,to a fill level measurement device comprising an antenna apparatus ofthis type, to the use of an antenna apparatus of this type fordetermining the viscosity of a moving liquid, to the use of an antennaapparatus of this type for determining a mass flow rate of a bulkmaterial on a conveyor belt, and to a method for determining thetopology of a filling material surface.

BACKGROUND

Fill level measurement devices or other measurement devices used in thefield of object monitoring emit electromagnetic waves or ultrasonicwaves that are reflected, at least in part, by the filling materialsurface or the corresponding object. The at least partially reflectedtransmission signal can then be picked up by the antenna unit of themeasurement device and evaluated by the electronic system connected tosaid antenna unit.

By scanning the surface, it is possible to determine the topology of thefilling material surface or of the object(s). In the field of fill levelmeasurement, “topology” should be understood to mean the shape of thesurface of the filling material. The term “topography” can also be usedin this context.

Such measurement devices for topology determination are often complex toproduce and also operate.

SUMMARY OF THE INVENTION

An object of the invention is to provide a device and a method fordetermining the topology of a filling material surface that can reducetechnical effort.

This object is achieved by the features of the independent claims.Developments of the invention can be found in the dependent claims andthe following description.

A first aspect of the invention relates to an antenna apparatus for afill level measurement device. The antenna apparatus comprises anantenna unit and a drive unit. The antenna unit is designed to emit ameasurement signal towards a filling material surface and to receive themeasurement signal reflected by the filling material surface. Thefilling material may be a moving liquid, but also may be a bulk materialarranged either in a closed container or in the open air.

The drive unit is designed to rotate the antenna unit about an axis ofrotation. Said axis of rotation can be a vertical axis of rotation, forexample, if the antenna apparatus is installed in or on a container.

The antenna unit comprises an array, i.e. an arrangement, made up of aplurality of radiator elements. The array is designed to emit andreceive the measurement signal.

The radiator elements are, for example, substantially two-dimensional,planar patches. They may also be the open ends of highfrequency-optimised waveguides, for example.

Furthermore, an elongate focussing arrangement is provided, which isdesigned to focus the measurement signal emitted by the antenna unit.The elongate focussing arrangement has a longitudinal direction thatextends in the longitudinal direction (referred to as the Y_(A)direction in the following) of the array. Said focussing arrangementalso has a transverse direction that extends in the transverse direction(also referred to as the X_(A) direction in the following) of the array.The longitudinal extension of the elongate focussing arrangement can begreater than the transverse extension.

According to an embodiment of the invention, the focussing arrangementcomprises a dielectric cylindrical lens, the longitudinal axis of whichis parallel to the longitudinal direction of the antenna unit. Accordingto another embodiment of the invention, the focussing arrangementcomprises a parabolic trough as a main reflector and a counter reflectorarranged at a spacing from the parabolic trough, the array for emittingthe measurement signal towards the counter reflector being arrangedeither on or near to the surface of the parabolic trough.

Using the elongate focussing arrangement, it is possible to focus themeasurement signal emitted by the array in one dimension (specificallyin the transverse direction of the antenna arrangement). Therefore, thefocussing arrangement assists with focussing the measurement signal inthe transverse direction. It may be provided that the focussingarrangement does not assist with focussing the measurement signal in thelongitudinal direction of the array. Electronic beam steering isprovided for this purpose.

According to another embodiment of the invention, the array is aunidimensional array, the one column of which extends in thelongitudinal direction of the antenna unit and therefore in thelongitudinal direction of the focussing arrangement.

In this case in particular, the focussing property of the focussingarrangement is very advantageous for improving focussing of themeasurement signal in the transverse direction.

According to another embodiment of the invention, the antenna apparatuscomprises a high-frequency unit for generating the measurement signal,the high-frequency unit being integrated in the antenna unit.

The high-frequency unit can be designed to generate and processhigh-frequency signals, for example in a frequency range of fromapproximately 75 to 85 GHz.

The high-frequency unit can also be integrated in the drive unit.

According to another embodiment of the invention, the array is atwo-dimensional array, the plurality of columns of which extend in thelongitudinal direction of the antenna unit and the plurality of rows ofwhich extend in the transverse direction of the antenna unit, theradiator elements of each column of the array being conductivelyinterconnected.

As a result, the measurement signals can be partially focussed in onedimension in a similar manner to when a dielectric lens or a parabolictrough is used. The two-dimensional array consequently representsanother embodiment of a focussing arrangement according to theinvention, for focussing the measurement signal is focussed in thetransverse direction.

Other devices for partially focussing the measurement signals that areknown to a person skilled in the art can of course be used. In addition,it may be possible to combine several arrangements of this type forpartial focussing in the transverse direction.

According to another embodiment of the invention, the antenna apparatuscomprises an electronic evaluation system, which rotates together withthe antenna unit when the antenna unit is rotated by the drive unit. Theevaluation system may be suitable for determining and designed todetermine the topology of a medium.

For example, the electronic evaluation system is located on the back ofthe antenna unit, i.e. on the side facing away from the fillingmaterial.

According to another embodiment of the invention, the electronicevaluation system is integrated in either the antenna unit or in thedrive unit.

According to another embodiment of the invention, the radiator elementsare arranged in one plane which, together with the axis of rotation ofthe antenna apparatus, forms an angle α that does not equal 90°. Theangle α is, for example, 45°. This can increase the measuring range ofthe antenna.

Another aspect of the invention provides a fill level measurement devicecomprising an antenna apparatus as described above and in the following.This is for example a fill level radar. The fill level measurementdevice may comprise an evaluation unit for determining the topologyand/or a value of a medium derived therefrom.

Another aspect of the invention provides the use of an antenna apparatusas described above and in the following, for determining the viscosityof a moving liquid.

Another aspect of the invention provides the use of an antenna apparatusas described above and in the following, for determining a mass flowrate of a bulk material on a conveyor belt.

Another aspect of the invention provides a method for determining thetopology of a surface of a filling material or bulk material, in whichan antenna unit is rotated about an axis of rotation. A measurementsignal is simultaneously emitted towards a filling material surface bymeans of the antenna unit. The emitted measurement signal is focussed bymeans of an elongate focussing arrangement and the measurement signalreflected by the surface of the filling material or bulk material isreceived by the antenna unit. The topology of the surface of the fillingmaterial or bulk material is then calculated from the receivedmeasurement signal. The antenna unit comprises an array made up of aplurality of radiator elements, which is designed to emit and/or receivethe measurement signal.

The array is, for example, a unidimensional array, i.e. a linear, serialarrangement of a plurality of radiator elements. A two-dimensional arraycan also be provided, in which the radiator elements in each row forexample are conductively interconnected.

In the following, embodiments of the invention will be described withreference to the figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a measurement device for recording the topology of afilling material surface.

FIG. 2 shows a further measurement device for recording the topology ofa filling material surface.

FIG. 3 shows a measurement device comprising an antenna device accordingto an embodiment of the invention.

FIG. 4 shows an antenna unit according to an embodiment of theinvention.

FIG. 5 shows an antenna unit according to another embodiment of theinvention.

FIG. 6 shows an antenna unit according to another embodiment of theinvention.

FIG. 7 shows an antenna unit according to another embodiment of theinvention.

FIG. 8 shows a measurement device according to an embodiment of theinvention for use to determine a mass flow rate of a bulk material on aconveyor belt.

FIG. 9 shows a flow diagram of a method according to an embodiment ofthe invention.

DETAILED DESCRIPTION OF EMBODIMENTS

The illustrations in the figures are schematic and not to scale.

Where the same reference numerals are used in different figures in thefollowing description of the figures, they denote the same or similarelements. However, the same or similar elements may also be denoted bydifferent reference numerals.

The present invention is applied to the field of fill level measurementdevices, but application in the field of object monitoring or mass flowrate recording is also possible and intended. Recording the topology ofa filling material surface can advantageously be applicable inparticular to measuring bulk materials and the resultant angles ofrepose and/or removal hoppers either inside or outside closedcontainers. However, it may also be possible to record the topology ofmoving liquids. This arises in a non-trivial manner, for example whenusing stirrers and the flow patterns on the liquid surface (tornados)generated thereby, and can allow conclusions to be drawn aboutadditional interesting variables, for example the viscosity or mixing ofthe filling material (taking into account the speed of the agitator ifnecessary).

FIG. 1 shows a fill level measurement device 101 which records an imageof the reflection properties in the container 104 by emitting a signal102 towards a filling material surface 103. The fill level measurementdevice or at least the transmission and/or receiving unit 105 of thedevice is able to change the main radiation direction 107 of thetransmission and/or receiving unit 105 by means of a mechanicaladjustment means 106 having a corresponding design, such that the entiresurface 103 of the medium in the container can be measured as part of ameasuring cycle. For this purpose, for example, the device can bepivoted in the X direction 108 and in the Y direction 109.

The fill level measurement device determines the topology from theplurality of echo curves recorded in the X direction and Y direction,i.e. the height profile of the filling material surface 103 as afunction of the particular location, which, for example, can be clearlydefined by the Cartesian coordinates X and Y.

Another possibility for changing the main radiation direction of themeasurement device is shown in FIG. 2. In contrast to the arrangement inFIG. 1, the measurement device 201 comprises a plurality of transmissionand/or receiving elements 202, which can be implemented inside a singleantenna 203 or can be distributed on a plurality of separate antennae.An antenna apparatus of this type can be referred to as an antenna arrayand can be used for digital beam shaping.

The fill level measurement device 201 changes the main radiationdirection 205, 206, 207 in order to determine the topology of thefilling material surface 204, either by changing the actuation signalsof the individual elements 202 in a targeted manner, and/or by digitallycalculating the echo curves recorded by the individual elements.

In purely mechanical solutions according to FIG. 1, a very complexmechanical construction 106 is required to carry out the mechanicaldeflection in the X and Y direction. Systems of this kind record manymeasurement points (for example 90×360 measurements each having 1 msmeasurement time, i.e. more than 30 seconds per measurement cycle), inorder to achieve high lateral resolutions in the X and Y direction.

Furthermore, systems of this kind have high mechanical wear on accountof the high rotational speeds required for achieving low measurementcycle times.

In purely electronic solutions for changing the main radiation directionaccording to FIG. 2, n times m individual transmission and/or receivingchannels need to be implemented separately. The indices n and m refer tothe number of individual emitting elements 202 in the particulardimension. The resultant complexity of electronic components can lead tohigh production costs of such devices, making the use thereof in severalapplications appear to be economically unviable.

Furthermore, when changing the main radiation direction electronicallyand in the case of very large deflection angles (for example larger than45° relative to the vertical), there is the problem that the width ofthe resultant antenna lobe increases significantly. Deflection of themain radiation direction 205, 206, 207 in the range of up to 90°relative to the vertical cannot be achieved in principle using systemsof this kind.

A basic concept of the invention involves combining specificadvantageous components of the above-described methods and devices. FIG.3 shows a first embodiment of the invention. The measurement device 301comprises a drive unit 302, a process coupling 303, a drive shaft 304and at least one antenna unit 305.

In the embodiment in FIG. 3, the entire upper region of the fill levelmeasurement device is denoted as the drive unit 302. The electronicevaluation system 313 is integrated in the drive unit and is connectedto the antenna array such that the measurement signals received by theantenna array can be transmitted to the electronic evaluation system313. Reference numeral 312 denotes a connection cable that can be usedto supply energy and exchange data.

In addition to the electronic evaluation system, the other electronicsystem of the fill level measurement device can also be integrated inthe drive unit 302.

Alternatively, the drive unit 302, the drive shaft 304 and the antennaunit 305 can form a modular unit that is connected to the actual mainbody of the fill level measurement device.

The antenna unit 305 emits the signals 306 generated by a high-frequencyunit 314 towards the filling material surface 307 to be measured. Inthis case, the high-frequency unit 314 can be integrated inside theantenna unit 305. Alternatively, the high-frequency unit can also beprovided in the region of the drive unit 302. In the embodiment in FIG.3, the high-frequency unit is arranged on the back of the antenna unit305.

The antenna unit 305 is rotatably mounted by means of the drive shaft304, and forms an angle α that does not equal 90° relative thereto. Anangle of 45°, which allows signals from large portion of the container308 to be recorded, has proven to be particularly advantageous.

If an angular range of ±45° is recorded by means of digital beamshaping, it is therefore possible, in combination with the rotation ofthe antenna, to measure the complete half-space containing the bulkmaterial. However, angles <45° are also possible in order to avoidambiguities, for example, in digital beam shaping or to improve theresolution.

A plurality of transmission and/or receiving elements are provided alongthe extension of the antenna 305 (Y_(A) direction). Each of theseelements is able to process signals from a wide angular range (forexample in the range of ±45° around the main direction of the antenna)along the extension Y_(A), while the individual elements along theextension X_(A) can also have clear transmission/receivingcharacteristics. The signals received individually by the elements canbe used, together with known algorithms for digital beam shaping, tochange the main radiation/receiving direction 309 of the antenna unit305 in a predetermined angular range. If an angular range of ±45°relative to the vertical main radiation direction 309 is selected inthis case, when taking into account the rotation 310 that also takesplace, each point of the surface 307 of the filling medium 311 in thecontainer 308 can be recorded by means of measurements.

The arrangement advantageously combines the advantages of mechanicallychanging the main radiation direction (in this case: rotation) withthose of electronic scanning. Very fast measurement rates (for exampleless than 10 seconds) can be achieved in this way, together with amechanically simpler construction (low rotational speed, typicallyapproximately 60 min⁻¹) and greatly simplified electronic systemcomplexity (for example on account of the unidimensional structure ofthe antenna array). A number of m<=20 elements is typically sufficientfor implementing the unidimensional array row.

FIG. 4-7 show possible embodiments of the antenna unit.

FIG. 4 shows a detail of a possible embodiment of the antenna unit 305.The antenna can consist for example of a unidimensional antenna array401 having m individual elements. The individual elements can beimplemented by printed circuit board patches having a correspondingdesign or by suitable waveguide ends or any other known emitting means.

In a first embodiment, the central individual element 402 can be used touniformly emit high-frequency energy towards the filling materialsurface 307 in an angular range that is as large as possible. Thesignals reflected by the filling material surface are received by eachof the elements of the antenna array 401, and are separately fed to adigital evaluation unit that is housed in the drive unit, for example.Using digital beam shaping algorithms, the evaluation unit is able tochange the main radiation direction of the antenna by combining thesesignals, in particular in an angle of ±45° relative to the vertical 309of the antenna unit.

At the same time, it will become clear at this point that the effortrequired for implementing separate transmission and/or receivingchannels can be significantly reduced by reducing the conventionallytwo-dimensional array arrangement 203 to a single dimension 401.

The conventional array arrangement 203 comprises a typically complexelectronic evaluation system circuit for each individual array element.The implementation effort is therefore reduced from n times m parallelcircuits of this type to just m individual circuits corresponding to them receiving elements.

The unidimensional array antenna 402 can achieve very effectivefocussing of the resulting antenna characteristics in the direction ofthe Y_(A) extension 403 by using the subsequent signal processing stepsfor digital beam shaping. Focussing in the direction of the X_(A)extension 404 (in this case this is the direction perpendicular to themain axis/longitudinal axis of the antenna array, in the plane of theantenna array), which, in combination with the rotation 310, actsprecisely in the radial direction, may be insufficient for certain uses.

Several approaches are advantageous for further improving thisbehaviour. On the one hand, it is possible to retain an embodiment usingthe antenna according to FIG. 4. If, during the subsequent signalprocessing, the Doppler shift resulting from the rotation of the antennais evaluated in the measurement signals recorded by the particular arrayelements, the resultant focussing in the transverse direction (radialdirection (X_(A) extension)) can be considerably improved. Thealgorithms used in this case can use the principles of SAR (syntheticaperture radar) and ROSAR (rotor synthetic aperture radar, based onrotating antennae).

Another possibility involves the use of patch antennae in an enlargementof the mechanical extension of the antenna structure in the direction ofthe X_(A) axis. FIG. 5 shows a corresponding example. The originallyunidimensional antenna array 401 is widened in the direction of theX_(A) axis 404 by means of additional patches 501. In order to keep thecomplexity of the associated electronic actuation system constant, theadditional patches are mounted at a defined spacing from the patches 402used up to now and are rigidly connected thereto by means of metalconnecting strips 502.

In contrast to other two-dimensional antenna arrays 203, the extensionof the originally unidimensional array is widened by the rigid metalconnecting strips 502, without requiring additional components foradditional high-frequency evaluation circuits.

Furthermore, it is possible to focus along the X_(A) direction using adielectric cylindrical lens. FIG. 6 shows the unidimensional antennaarray 401 described thus far, which comprises a cylindrical lens 601mounted thereabove.

The cylindrical lens shown in FIG. 6 comprises a base 603, to which theradiator elements 401 are attached. The curved surface 602 of thecylindrical shell spans thereabove. For example, the unidimensionalarray 401 is arranged in the focal point of the cylindrical lens.

Another embodiment, which is particularly advantageous, provides the useof a parabolic trough as the main reflector in conjunction with aunidimensional Cassegrain antenna arrangement. FIG. 7 shows acorresponding example. In conjunction with a counter reflector 701 (forexample a hyperbolic trough) having a corresponding design and theparabolic trough 702, the unidimensional antenna array 401 is highlyfocussed in the direction of the X_(A) axis 404, rendering the use ofthe arrangement shown in conjunction with the measurement device 301according to the invention particularly advantageous.

In the embodiment in FIG. 7, the unidimensional antenna array 401 islocated on the curved, reflective surface of the parabolic trough 702and radiates towards the counter reflector 701. The measurement signals703 emitted are first reflected by the counter reflector towards thecurved surface of the parabolic trough 702, and are then focussed fromthe curved surface of the parabolic trough 702 towards the fillingmaterial surface.

Furthermore, it is however also possible to use focussing devices thatare not explained in this case for focussing in the X_(A) direction andto combine these with a mechanical rotation.

FIG. 8 shows a conveyor belt 801, on which a bulk material 802 istransported. The bulk material forms an uneven surface 803, which can bemeasured by the measurement device 301. The measurement device 301 canbe, for example, a fill level measurement device, for example a filllevel radar device, which, in addition to the topography of the bulkmaterial surface, can also calculate and output the fill level of thefilling material.

FIG. 9 shows a flow chart of a method according to an embodiment of theinvention. In step 901, an antenna unit is rotated about an axis ofrotation, for example a vertical axis of rotation, either continuouslyor in stages. In step 902, the antenna unit emits a measurement signal,which is wide in the Y_(A) direction, towards a filling materialsurface. In step 903, the measurement signal reflected by the fillingmaterial surface is received by the individual elements of the antennaunit. In step 904, echo curves are calculated from various mainreceiving directions of the antenna unit in the angular range to bemeasured by means of digital beam shaping.

The method then returns to step 902, followed by step 903, followed by arepeated digital scan across the angular range to be measured in theY_(A) direction by means of electronic beam steering (step 904). Steps902-904 can now be carried out as often as necessary until a completedata set (several measurement points during one rotation) is recorded.

Lastly, in step 905 the topology of the filling material surface and/orthe fill level is calculated from the measurement signals obtained bythe antenna unit by means of digital beam shaping in the angular rangescanned in step 901.

The invention therefore provides a device and a method for focussing aradar signal along a line which is guided over the surface of a fillingmedium by means of rotation. The topology of the medium in the containercan be ascertained from the echo curves recorded from said focussingprocess. In particular, it may be provided that a substantiallyunidimensionally emitting antenna array, which allows for echo curves tobe recorded along a first axis by means of digital beam shaping, iscombined with a mechanical rotation about a second axis, so that it ispossible to record echo curves from a two-dimensional field. These twoaxes are typically perpendicular to one another.

The invention therefore reduces the mechanical effort and the mechanicalstrain on a rotary antenna arrangement by combining said arrangementwith a unidimensional antenna array, and this can optimise the length oftime for recording echo curves in addition to the cost-effectiveness ofthe solution.

It should also be noted that “comprising” and “having” do not excludethe possibility of other elements or steps, and “one”, “a” or “an” doesnot exclude the possibility of a plurality. It should further be notedthat features or steps which have been described with reference to oneof the above embodiments may also be used in combination with otherfeatures or steps of other above-described embodiments. Referencenumerals in the claims should not be treated as limiting.

The invention claimed is:
 1. An antenna apparatus for a fill levelmeasurement device, comprising: an antenna configured to emit ameasurement signal towards a filling material surface and to receive areflected measurement signal reflected by the filling material surface;a motor configured to rotate the antenna about an axis of rotation; andan elongate focussing arrangement configured to focus the emittedmeasurement signal and/or the reflected measurement signal, wherein theantenna comprises an array of a plurality of radiator elementsconfigured to emit the measurement signal and/or to receive thereflected measurement signal.
 2. The antenna apparatus according toclaim 1, wherein the elongate focussing arrangement comprises adielectric cylindrical lens having a longitudinal axis that is parallelto a longitudinal direction of the antenna.
 3. The antenna apparatusaccording to claim 1, wherein the elongate focussing arrangementcomprises a parabolic trough as a main reflector, and a counterreflector arranged at a spacing from the parabolic trough, and whereinthe array is further configured to emit the measurement signal towardsthe counter reflector and is arranged either on or near to a surface ofthe parabolic trough.
 4. The antenna apparatus according to claim 1,wherein the array is a unidimensional array, having one column extendingin a longitudinal direction of the antenna.
 5. The antenna apparatusaccording to claim 1, wherein the array is a two-dimensional array,having a plurality of columns extending in a longitudinal direction ofthe antenna, and a plurality of rows extending in a transverse directionof the antenna, and wherein radiator elements of the plurality ofradiator elements in each column of the plurality of columns areconductively interconnected.
 6. The antenna apparatus according to claim1, further comprising: a high-frequency signal generator configured togenerate the measurement signal, the high-frequency signal generatorbeing integrated in the antenna.
 7. The antenna apparatus according toclaim 1, further comprising: an electronic evaluation system configuredto rotate together with the antenna when the antenna is rotated by themotor.
 8. The antenna apparatus according to claim 7, wherein theelectronic evaluation system is integrated in either the antenna or inthe motor.
 9. The antenna apparatus according to claim 1, wherein theplurality of radiator elements are disposed in one plane that forms anangle α with an axis of rotation of the antenna that does not equal 90degrees.
 10. The antenna apparatus according to claim 9, wherein theangle α is 45 degrees.
 11. A fill level measurement device comprising anantenna apparatus according to claim 1, wherein the fill levelmeasurement device comprises digital evaluation circuitry configured todetermine a topology of a medium in a container.
 12. The fill levelmeasurement device according to claim 11, the device being furtherconfigured to determine a viscosity of a moving liquid.
 13. The filllevel measurement device according to claim 11, the device being furtherconfigured to determine a mass flow rate of a bulk material on aconveyor belt.
 14. A method for determining a topology of a surface of afilling material or a surface of a bulk material, comprising: rotatingan antenna about an axis of rotation, the antenna comprising an array ofa plurality of radiator elements; emitting, by the antenna, ameasurement signal towards and/or receiving a reflected measurementsignal from a filling material surface; focussing, by an elongatefocussing arrangement, the emitted measurement signal and/or thereflected measurement signal; receiving the reflected measurement signalreflected by the surface of the filling material or the surface of thebulk material; and calculating the topology of the surface of thefilling material or the surface of the bulk material from the receivedmeasurement signal.
 15. The antenna apparatus according to claim 1,wherein the elongate focussing arrangement comprises a dielectriccylindrical lens having a longitudinal axis that is parallel to alongitudinal direction of the antenna, wherein the array is atwo-dimensional array, having a plurality of columns extending in alongitudinal direction of the antenna, and a plurality of rows extendingin a transverse direction of the antenna, and wherein radiator elementsof the plurality of radiator elements in each column of the plurality ofcolumns are conductively interconnected.
 16. The antenna apparatusaccording to claim 1, wherein the elongate focussing arrangementcomprises a parabolic trough as a main reflector, and a counterreflector arranged at a spacing from the parabolic trough, wherein thearray is further configured to emit the measurement signal towards thecounter reflector and is arranged either on or near to a surface of theparabolic trough, wherein the array is a two-dimensional array, having aplurality of columns extending in a longitudinal direction of theantenna, and a plurality of rows extending in a transverse direction ofthe antenna, and wherein radiator elements of the plurality of radiatorelements in each column of the plurality of columns are conductivelyinterconnected.